Signal type torque indicating wrench



Jan. 16, 1951 M. HATTAN SIGNAL TYPE TORQUE INDICATING WRENCH OriginalV Filed July 8, 1944 NNVI Patented Jan. 16, 1951 SIGNAL TYPE TORQUE INDICATING WRENCH ..1 v ll-lattan, Dayton, Ohio Original vapplication July 8, '1944, Serial No.

544,127. Divided and this application February 13, 1945, Serial No. 577,721 j l solaires; (ci. 814525K).

(Granted under the act of March 3, 1883, as I amended April 30, 1928; 370 0.-

The invention described herein may be manufactured and us'edby 'or for the Government for governmental purposes, without the payment to me of any royalty thereon l.

This application is a division of my copending application Serial No. 544,127, filed July 8, 1944, and now matured into Patent No. 2,474,247, of June 28, 1949.

In accordance with the invention, as fully set forth in my copending application, various types of wrench work heads may be applied to the wrench to adapt itself to various working requirements. This feature of my invention is brought about by providing a scale on the wrench calibrated in torque units about a torque axis which lies outside the physical confines of the wrench body and a detailed description of the structure and operation of the invention now follows with reference to the appended drawing, in which Fig. 1 is a longitudinal cross section of one form of my invention;

Fig. la is a detailed showing of a socket member in place on the wrench illustrated in Fig. l;

Fig. lb is an enlarged detail of one element of the form shown in Fig. l.

Fig. 2 is an exterior view of the form shown in Fig. 1;

Fig. 3 is a longitudinal cross section of another form of my invention; and

Fig. 3a is a fragmentary exterior view of the wrench of Fig. 3 with a portion cut away to show a torque indication scale.

Referring to Figures l and 2, a wrench handle member is shown having a hollow cylindrical wrench body I secured to a hollow cylindrical handle 2 as by threading 3. Within body I is a generally tubular flexure element 4 having an end protruding therefrom adapted for attachment to a work head 4l carrying a socket member 5 (Figure la). pivotally secured at to body I whereby relative angular movement is provided between the free end 4a of ilexure element 4 and a sleevelike taper member il slidably disposed within body I and adapted to transmit torque stress from handle 2 to fiexure element 4. The tapered surface 9 of taper member 8 is concentrically spaced from the free end 4c of flexure element 4, the concentric spacing being variable by reciprocating taper member S relative to said free end 4c. Reciprocal movement of taper member 8 is obtained by means of a sleeve Ill (Figure lb) rotatably mounted on body I and provided with an internal spiral groove i I coacting with spherical bearings I2 which `are maintained in diametrically opposed relationship by longitudinal slots I3 cut through the walls of the body I, the spherical bearings I2 being retained in a peripheral groove I4 provided externally on the taper member 8. The ro- Flexure element or beam member 4 is i tatable sleeve I0 is restrained against axial movei menton body I by a shoulder I6 thereon and by a sleeve l1 secured in any suitable manner on body t `I such Aas by a 4shrinlr iit. The rotatable sleeve I0 is externally knurled as indicated at I8 and is provided with a scale I9 calibrated in torque'units and adapted to cooperate with a fixed index mark Illa provided on body I to indicate the torque setting of the wrench. Rotation of the sleeve II) will, by virtue of the spiral groove II, exert a longitudinal thrust on the spherical bearings I2 in a direction depending upon the direction of rotation of the sleeve ID, the longitudinal thrust on spherical bearings I2 being transmitted to taper member 8 by reason of the retention of the spherical bearings I2 in the peripheral groove I4 on taper member 8. Accordingly, the concentric spacing between the tapered surface 9 and the free end 4a of ilexure element 4 may be predetermined by the operator by rotary adjustment of the sleeve IB to effect reciprocal motion of the taper member 8 relative to said free end 4a. It will now be apparent that owing to the pivotal relationship provided at 6 between body I and flexure element 4, a movement of handle 2 in a torque applying direction will not transmit any torque force to the work head until taper member 8 has moved angularly with body member I relative to the free end 4a of flexure element 4 to the point where the tapered surface 9 abuts free end 4c. The extent of this noload or lost motion movement of handle 2 depends on the amount of initial concentric spacing provided between the tapered surface 9 and the free end 4a by the adjusted position of taper member S relative thereto, the purpose of the lost motion movement being to provide a predetermined spacing between electrical contact elements as will presently appear.

Rigidly supported at 2t within flexure element 4 and concentrically spaced from the inner walls thereof is a contact rod 2l having a contact ele ment comprising a free end 2 la adapted to elec trically contact either of a pair of contact screws 23, depending on the direction of torque movement of handle 2. Screws 23 are adjustably secured in a member 24 movable in a torque applying direction with the handle 2. Relative angular movement of the electrical contacts is obviously effected during the no-load movement of handle 2 whereby an initial spacing between the contacts predetermined by the extent of said noload movement is realized. The torque stress transmitted from handle 2 to iiexure element 4 through abutment of the free end 4a thereof with tapered surface 9 subsequent to no-load movement serves to iiex the tubular portion of flexure element 4 and simultaneously decrease the initial spacing between the Contact elements to the point where electrical contact is obtained, it being noted that said contact rod 2l remains substantially straight and unaffected by the ilexure of iiexure element 4. The function of the contact rod 2l is to provide for coaction of the contact elements at a point substantially removed from pivot 6 whereby the arc of relative movement of the contacting elements is enlarged for l structural convenience.

Member 24 is electrically insulated from ground by means of insulating washers 25 and 2l and insulating collar 28. Suitable ports are provided in insulating collar 23 in alignment with ports 29 in body member l whereby access to contact screws 23 may be had for adjustment thereof. Member 24 abuts the center terminal of a signal lamp 3Q supported within and in electrical contact peripherally with a collar 33, slidably retained and insulated from ground in a translucent, colored plastic sleeve 34 disposed within the handle 2. A spacer tube 25 is slidably disposed within the translucent sleeve and abuts collar 33 whereby biasing action of a spring 36 is transmitted through a series of cells .il to the outer end of spacer tube 35 for the purpose of maintaining electrical contact between extremity 24a of member 24 and the center terminal of signal lamp Si?. An end cap 39 is provided for retaining the spring 36l in compression against the negative casing electrode of the outermost cell thereby establishing a series connection of the cells to form a battery disposed Within a battery holding sleeve 4D which is provided for protection of the inner surface of handle 2 in the event of one or more of the cells swelling or bursting its casing and loosing a corrosive electrolyte. VAlthough three cells are' shown, it will be appreciated that the device is not limited to any specific number. The peripheral casing terminal of signal lamp 3E! is electrically connected through spacer tube 35 to the positive center terminal of the battery, the negative terminal thereof being grounded through spring 3G. The center terminal of signal lamp 3Q in electrical contact with the extremity 24a of member 24 is insulated from ground. Accordingly. any movement of handle 2 in a torque applying direction suiiicient to bring either of the Contact screws 23 into contact with the free end 2 la of contact rod 2l will complete a circuit through ground from the negative casing terminal of the'battery to the center terminal of the signal lamp 3! whereby the signal lamp will be lit, the, illumination thereof being visible exteriorly of 'handle 2 via ports il and #i2 in spacer tube 35 and handle 2. respectively, the intermediate translucent, colored plastic sleeve 34 imparting its characteristic color to the light rays to enhance noticeability.

In operation. the sleeve lf3 is manually rotated to bring a desired torque indicium of scale i9 opposite the fixed index mark lila on body member l. The rotation of sleeve iii serves to x the position of taper member in relation to the free end 4a of ilexure member l whereby the concentric .spacing between free end 4a and the tapered surface il of taper member 8 is determined. Since iiexure member 4 is pivotal-ly related to handle member 2, a definite degree of lost motion is provided between free end 4a and the tapered surface 9, as heretofore described. When handle 2 is operated to apply working torque, the initial movement thereof takes up the lost motion, and one or the other of contact screws 23, depending upon the direction of torque rotation of handle member 2, is brought proportionally closer to the free end 2 la of contact rod 2 l. This initial motion transmits no torque stress to flexure member 1i until the lost motion has been entirely taken up, i. e., at the end of the no-load movement when some portion of the tapered surface Q will abut free end 4a. Continued motion of handle member 2 will cause a deflection of the tubular portion of ilexure member 4, said deflection increasing proportionally with the torque stress applied to handle member 2 until a contact screw 23 approaching the free end 2id of contact rod 2| closes contact therewith. At that instant a circuit through the battery and signal lamp 3G is completed, thereby lighting the lamp, the light thereof being visible to the operator as heretofore described.

In the event of an overload being appliedbeyond the stress for which iiexure element 4 is designed, the shoulder i4 thereon abuts the portion 45 of body l to take the excess stress, thereby protecting flexure member si from being stressed beyond its proportional limit.

As will be apparent from the structure, when taper member t is set at the right as viewed in Figure l., the lost motion is greatest, whereby one Contact screw 23 is relatively close to the free end 2 la of contact rod 2l at the end of the no-load movement; accordingly, only a small deflection of .iiexure member 4 will take place as handle 2 moves said contact screw 22 into contact with said free end 2id during the subsequent torque load movement. Conversely, when taper member 2 is set at the extreme left, the no-load movement is least; consequently, a greater deflection of ilexure member 4 will take place in the ensuing motion of handle member 2. Accordingly, the degree of torque exerted before the signal lamp 3B lights is determined by the degree of lost motion taken up during initial no-load movement of handle 2, which is dependent upon the adjusted axial position of taper member 8 relative to the free end 4a of exure member 4.

Adjustability of contact screws 23 is provided as a manufacturing convenience so that a zero setting may be obtained; and also from time to time as usage of the wrench causes wear and tear on the parts and affects the elasticity of the iexure member 4, resetting to zero may be desirable. This feature is a refinement and not essential to the usefulness of the wrench for general conditions. In adjusting the zero setting, the wrench is held with the axis of the screws 23 vertical and the upper screw adjusted so that the signal lamp 35i just lights with the scale i9 set to Zero and the wrench supported to the handle with no torque load other than the weight of the other end. Each screw 23 is adjusted in the upper position, since that is the position wherein contact is made with the free end 2la of contact rod 2| when the weight of one end of the wrench is used to produce a torque stress.

The axially extending outer end portion of the flexure element 4 is adapted to be received within a work head or adapter head 4l provided with a socket 4l and the interiitting parts are releasably'retained in connected relation by means of a spring biased ball detent Sii. vA keying pin 5l extends throughthe flexure element 4 and engages the sides of open ended slots 52 cut into the rim olf-work head 4i' for the purpose of preventing relative rotary motion therebetween. The work engaging socket member 5 is detachably affixed to the work head 4l by means of a non-circular stud 228 on the work head extending into a similar noncircular opening in the socket member. The stud is provided with a spring biased ball detent 49 which aids in retaining the socket member in place on the stud.

The calibration of torque scale I9 is calculated for a torque aXis extending axially through the socket carrying stud 48, as illustrated on Figure 2. The torque axis lies outside the physical confines of the wrench body, an important aspect, since such a construction permits the design and attachment of various types of work heads, e. g., a tubing nut type, as illustrated in Figure 3, directly to flexure member 4, provided that such other type is designed to have its torque axis identical with that shown for the adapter 41. Accordingly, a single calibrated scale is operable in conjunction with a variety of work heads. Work heads of various types may be attached to exure element 4 in the manner shown for the adapter 41 by being constructed to coact with ball detent and keying pin 5l. Likewise, special adapters to hold various types of work heads may be constructed, e. g., the specific adapter 41 shown is intended for use with various sizes of socket members similar to the member 5.

A further feature of the invention resides in the use of the translucent, colored plastic sleeve 34, both as an insulating means and as a means for enhancing visibility of the light rays. It has been found in practice that a red colored sleeve produces a quality of light which is very distinguishable. The sleeve 34 is used in coniunction with frosted plastic inserts in ports 42. The purpose oi inserts 55 is to weaken the incident and reflected. rays of outside light whereby contrast with the direct rays from the signal lamp is increased promoting visibility7 to the opera- I' tor when working in strong light` Also. the depth of the ports A2 in relation to their diameter has a shading effect against outside light, the frosted plastic inserts 55 preventing ports G2 from filling un with oil and grease.

In the modification shown in Figure 3, Bil is a handle threadedly secured to a body 5l and arially adjustable relative thereto. A lock nut 65 is provided to secure handle member' till in adjusted position. Pivotally supported at B2 within body hl is a work head holding member E3 adapted for attachment to a work head 64. AX- ially supported within member 63 and electrically insulated therefrom by a plastic cup 66 is a ileXure member 61 having a tapered end 68 abutting the button 59 slidably disposed within an insulating plastic sleeve 1G. A spring 11 is in compression between button 69 and a slidable button 12 for electrical contact with the negative casing electrode of dry cell 13 housed within the handle t0. A signal lamp 16 is held in a clip 11 supported within a can 18 threadedly secured at the extremity of handle Gil. A colored, translucent plastic cap 19 abuts the peripheral edge of clip 11 and is held in position in the cap 18 adjacent ports 853 by the biasing action of spring 1l transmitted through button 12, dry cell 13, signal lamp 16 and clip 11. The positive center electrode of dry cell 13 abuts the center terminal of signal lamp 15. Consideration of the structure will make it apparent that the negative side of the dry cell 13 is electrically connected to flexure member 6l through button 69, spring 1l and button 12, all aforementioned elements being electrically insulated from ground by sleeve 1D and plastic cup E56. The peripheral casing terminal of signal lamp 1S is grounded.

In view of the pivotal relationship provided at 62 between the sleeve 1B and the tapered end 68 of flexure member 61 when handle 60 is adjusted relative axially to the body member 6l, a specific degree of lost angular motion is provided between the sleeve 10 and the tapered end 63 by virtue of the taper provided thereon. As the handle member is adjusted axially outwardly, the lost angular motion between sleeve 10 and the tapered end 68 of iiexure member 6.1 may be seen to increase, whereby initial motion of the handle member 6U in a torqueapplying direction will have a corresponding no-load movement. Conversely, as the handle member is adjusted axially inwardly, the lost angular motion between sleeve 10 and tapered end 68 of exure member 61 is decreased, whereby the corresponding no-load movement of handle member is lessened. Subsequent to a no-load movement of either high or low degree, an abutting action between the inner peripheral edge of the sleeve 10 and some adjacent portion of the tapered end 68 of eXure member 61 will result and the ensuing bowing effect on flexure member 61 will cause the center portion thereof to contact the surface of the surrounding bore 3l in handle 50. Accordingly. the negative casing electrode of the dry cell 13 will be grounded whereby a circuit will be cornpleted through the signal lamp 16, the illumination thereof being visible to the operator through the colored, translucent plastic cap 19 and the ports 80. In the specic illustration of Figure 3, the handle member 6U is shown as screwed to the inward limit of its motion relative to the body member el, the tapered end 6B of the exure member 61 then protruding as far into sleeve 1U as it is. possible for it to go whereby a small degrec of lost motion is provided in relative angular movement therebetween. The lock nut 65 is shown tightened against the outer end of the body `member 5! to secure the handle member 68 in position. In this specic illustration, the wrench is set for the uppermost limit of the toroue range inasmuch as movement of the handle Bil in torque applying direction will in volve the least possible no-load movement prior to transmission of torque stress to the fleXure member 61, whereby the spacing between the central portion thereof and the internal surface of the bore 3! within the body member 6i will be relatively large at the end of the no-load movement, thus necessitating a relatively large flexure of the flexure member El to produce a contact. corresponding to a large torque stress.

Calibration in torque units of a wrench of the type shown in Figure 3 has been provided in practice by means of a simple longitudinal scale on the exterior of handle (it whereby distances relative to the edge 82 of lock nut S5 are readable in torque units for convenience in setting the wrench to operate the signal lamp when a desired `degree of torque is reached (see 3a). Inasmuch as the change in bending resistance of the flexure member B'i at various settings along the tapered end 8 introduces factors which complicate Calibrating type of wrench by a purely mathematical process, it has been found feasible to provide a scale calibrated empirically rather than by calculation.

It will be understood that my invention is not limited to the specific structures herein disclosed. but is capable of modification without departing from the spirit thereof and I seek protection of United States Letters Patent for the novel fea tures and structure set forth in the appended claims.

I claim:

l. In a torque indicating wrench, an elongated tubular wrench body having a handle end and a work head end, a fiexible beam member mounted for limited rotation within said body on a pivot adjacent to said Work head end thereof, abutment means within said body for engagement with one end of said beam member to transmit torque stress from said body to said beam member, the other end of said beam member having an integral rigid projection extending longitudinally from said body at said work head end thereof and forming means adapted to interchangeably receive selected work heads in intertting and non-rotatable relation therewith, said work heads each having a projectionreceiving socket and also a nut-receiving socket for. non-rotatable application to a nut or stud, any selected work head when tted onto said projection providing a nut-receiving socket the central axis of which extends transversely of said Wrench and is located a xed distance from said pivot and beyond said projection, cooperating means mounted on said body and said beam member adapted to actuate a signal upon application of a predetermined torque through said beam member to said selected work head, and said central axis of said nut-receiving socket'of a selected Work head forming the torque axis for the determination of said predetermined torque.

2. In a torque indicating wrench, an elongated tubular Wrench body having a handle end and a work head end, a exible beam member mounted for limited rotation within said body on a pivot adjacent to said work head end thereof, abutment means within said body for engagement with one end of said beam member at opposite sides thereof depending on the direction of torque to be exerted by said wrench, the other end of said beam member having an integral rigid projection extending longitudinally from said body at said work head end thereof and forming means adapted to interchangeably receive selected work heads in interfitting and nonrotatable relation therewith, said work heads each having a projection-receiving socket and also a nut-receiving socket for non-rotatable application to a nut or stud, any selected work head when tted onto said projection providing a nutreceiving socket the central axis of which extends transversely of said wrench and is located a fixed distance from said pivot and beyond said projection, cooperating means mounted on said body and said beam member adapted to actuate a signal upon application of a predetermined torque through said beam member to said selected work head, and said central axis of said nut-receiving socket of a selected work head forming the torque axis for the determination of said predetermined torque.

3. A torque indicating wrench comprising an elongated spring beam, a handle member associated with one end of said beam for the application of torque to a piece of work through said beam, a substantially inflexible member joined at one end thereof to the other end of said beam to form a longitudinally extending continuation thereof and having a free end portion, means pivotally mounting said inflexible member on said handle member, an adapter member having one portion detachably engaging the free end of said iniiexible member and another portion disposed outwardly beyond said rst portion having a torque axis arranged parallel with the axis of said pivot means and at right angles to the normal plane of exure of said beam and located at a predetermined fixed distance from the point of juncture of said beam with saidV inflexible member, and torque indicating means calibrated on the basis of said iixed distance for measuring the torque applied about said torque axis to a piece of Work as said beam is iiexed.

4. A torque indicating wrench comprising an elongated spring beam, a handle associated with one end of said beam for the application of torque to a piece of work through said beam, a substantially inflexible member rigidly connected at one end with the other end of said beam and in alignment with the axis of said beam when the latter is unflexed and having a free end providing an attachment portion, an adapter inember having a first portion detachably and rigidly engaging said attachment portion on said inflexible member for positioning said adapter in a predetermined iixed position on the latter and a second portion having a torque axis intersecting said axis of said spring beam and normal to the plane of flexure of said spring beam and located at a predetermined ixed distance from the juncture of said beam with said inflexible member, a work-engaging member detachably and rigidly engaging said second portion of said adapter, and torque indicating means operable by relative movement between said handle and said inflexible member and calibrated on the basis of said fixed distance for measuring the torque applied about said torque axis to a piece of work when said beam is flexed.

5. A torque indicating wrench comprising an elongated spring beam, a handle associated with oneend of said beam for the application of torque to a piece of work through said beam, a substantially iniiexible member rigidly connected at one end with the other end of said beam and in alignment with the axis of said beam when the latter is unflexed, an attachment element at the other end of said inexible portion and rigid therewith, a work-engaging member having an attachment portion detachably and rigidly engaging said attachment element for positioning said work-engaging member in a predetermined fixed position on said attachment element and a work-engaging portion having a torque axis intersecting said axis of said spring beam and normal to the plane of lexure of said spring beam and located at a predetermined fixed distance from the juncture of said beam with said infiexible member, and torque indicating means operable by relative movement between said handle and said inexible member and calibrated on the basis of said xed distance for measuring the torque applied about said torque axis to a piece of Work when said beam is exed.

MARK HATTAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,847,640 Cairncross et al Mar, l, 1932 2,265,501 Sunnen June 25, 1940 2,2%,081 Pagnard Dec. 30, 1941 2,332,971 Johnson Oct. 26, 1943 2,365,486 Morris Dec. 19, 1941i 2,381,226 Parker Aug. 7, 1945 2,486,103 Billeter Oct. 25, 1949 FOREIGN PATENTS Number Country Date 752,175 France July 10, 1933 

